All of them have spent the weekend on the phone, doing the numbers and shoring up support.

So how's it looking?

National has 56 MPs, meaning the magic number to get to is 29 votes. On Sunday, this is what the numbers looked like:

Simon Bridges has around 23 votes, while Amy Adams is up there too with 22 MPs supporting her. In third place is Steven Joyce with five votes, then it's newbie Mark Mitchell with four votes and in last place is Judith Collins, with two votes - one is her own.

No one has an outright majority at the moment, meaning the bottom placed candidate will drop off on each voting round until someone gets to 29.

And the stakes are high.

A well-placed source in Camp Bridges told Newshub it's very close to the line and he's almost there. Camp Adams claimed the same, with a source telling Newshub she will pick up a big chunk of support in the second vote.

There's a wildcard though: Steven Joyce. His team rejects these numbers and told Newshub it's not a two-horse race, but a three-horse race, and that Mr Joyce has a good shot.

Camp Collins also said Newshub's numbers were wrong, and she's doing significantly better than she was last week.

As for Camp Mitchell, they weren't picking up the phone.

Publicly all of them claim they have the numbers. But someone is wrong and none of them are wanting to admit defeat until Tuesday.